Mother's milk and hydrogen peroxide.

H(2)O(2) levels in mother's milk were measured at different times of postpartum periods after birth as well as after different times of storage at freezing temperature. The luminol H(2)O(2) dependent chemiluminescence at pH= 9.8 technique was used. Maximum levels of H(2)O(2) were found in the first week of the postpartum period (24.992 +/- 0.168 microM). The levels of H(2)O(2) decreased significantly (P<0.05) in the second week (20.4 +/- 0.169 microM), while a significant (P<0.01) decrease in the level of H(2)O(2) occurred in the third week after birth (15.783 +/-0.782) microM. The levels of H(2)O(2) fell sharply in the fourth week of lactation (8.75+/- 0.27 microM) with a significant difference relative to the first week (P<0.001). The stability of the H(2)O(2) levels remained constant, at least for a period of one month, with storage at freezing point for all groups (P>0.05).